The dashboard paneling or door paneling of a vehicle comprises a covering layer which serves as a boundary to the passenger compartment. It generally comprises a support layer, a foam layer and a film. If less value is placed on esthetic requirements in the vehicle interior, whether for cost reasons or because of increased demands on the robustness of the dashboard paneling, for example in the case of commercial vehicles or off-road vehicles, it can be limited to the support layer. This support layer is produced, for example, from polypropylene by injection molding. As an alternative, the support may be coated with a decorative film. A weakened structure is provided in the paneling, which structure makes it possible for a safety mechanism which is mounted behind the paneling and is invisible to the passenger to be triggered in the event of an emergency and to pass explosively through the paneling. In order to increase the safety of the passengers, airbag devices are mounted at various points in motor vehicles. The airbag devices are mounted in the interior paneling of the vehicle in a manner such that they are invisible to the passenger and can be provided in the door side paneling, in the A-pillar, in the roof section, in the dashboard, under the seats or in the steering column. If the airbag is triggered, the structure of the vehicle interior paneling has to be destroyed. If a weakened area were not provided, the triggering would proceed in an uncontrolled manner and parts of the vehicle interior paneling would be blasted away. The explosive force required in order to puff out the airbag in good time in the event of a crash can have the effect that parts of the interior paneling are torn off at the same time into the passenger compartment and can cause the occupants severe injuries. All of the airbag devices known from the prior art and a few of which have already been mentioned by way of example mention this problem.
When the airbag is triggered, in order to protect the occupants from splintering parts, a connection is provided between the dashboard paneling, or more precisely the support layer thereof, and the triggering mechanism.
Airbag covers are generally pulled back into the module housing by a mechanism. This pull-back mechanism can comprise deflecting rollers, slides, hinges or the like. In the case of all known pull-back devices, this requires increased space on the engine side of the dashboard or steering column, which side is invisible to the occupant. This required space increases the required longitudinal dimensions of the component accommodating the airbag, for example, the dashboard support, the door side paneling, the steering column or one of the A, B, C pillars, i.e. the connecting struts which are used for accommodating the windshield, doors and roof construction. Pull-back devices actuated by gas or hydraulic cylinders require at least one separate space behind the actual airbag module.
For example, the following airbag triggering mechanisms are known from the prior art:
DE10001040 (Autoliv) A tension band which is mounted in each case at one end of the covering flaps holds the covering flap in an open position while the surface tears open at the (centrally) mounted predetermined breaking point. In this case, the covering flap parts protrude a good distance into the vehicle interior, with the result that it cannot be ruled out that occupants who are in a position which does not correspond to the standard position, when the airbag is triggered, may become injured.
DE19750182 (Autoliv) Covering flap with a lifting unit to which gas is admitted and which displaces the flap parts to the rear when the airbag is actuated. Although this solution permits the covering flap parts to be pulled back, it requires additional structural space in that region of the dashboard which faces away from view.
DE19855909 (TRW) Opening of the airbag causes lateral pushing away and sliding off of the two covering flap parts. In this design, a gas generator which is to be installed separately is also required, said gas generator requiring a relatively large structural space behind the airbag covering (on that side of the dashboard which faces away from view).
DE19958585 The gas pressure deforms a piston which acts on a pull cord or film which is connected to outer ends of the covering flaps. The deformation or displacement of the piston causes tensioning of the pull cord, and therefore tears open the flap and the airbag can emerge through the interior paneling structure. The relatively complicated design of the gas channels also has the effect of enlarging the structural space behind the interior paneling.
DE19860932 (Petri) shows a multi-part airbag with various unfolding directions. This patent shows the necessity of providing different construction variants for opening the covering flaps in order to take into account the different stages of the unfolding of the gasbag and directions of expansion of the gasbag.
DE 19860933 (Petri) deals with an airbag in the roof region, comprising two sections which are unfolded at an angle to each other. As already illustrated in DE19860932, the special opening sequences and the arrangement of airbags often result in only very small structural spaces which are only available to the opening mechanism. In a further design, a retaining band is fastened to the airbag or the airbag is constricted. If the covering flaps are pulled away laterally, the airbag can also be unfolded unhindered using the construction according to the invention, and also local constrictions which contribute to better protection for the occupants can be integrated in the airbag construction.
The airbag device WO0114172 (Inova) is pulled back, so that part of the vehicle interior paneling is pulled back into the dashboard by a pull-back mechanism actuated by gas pressure, electrically or mechanically. This construction avoids the flinging of paneling parts into the vehicle interior and permits unhindered unfolding of the airbag. If, however, the actuation takes place by a mechanism which does not use the gas pressure, which is in any case released when the airbag is triggered, disturbances in synchronization may occur, since individual, electrically controlled circuits may fail in the event of a crash. A further disadvantage of this arrangement is the large requirement for structural space behind the actual airbag and the triggering mechanism.